Phytosulfokine (PSK) alpha peptide

• COA/MS/HPLC Report
• Handling and Storage of Synthetic Peptides
• Material Safety Data Sheets (MSDS)

Batch to batch variation of the purity

Phytosulfokine-alpha (PSK-α) is a sulfated pentapeptide with the structure H-Tyr(SO₃H)-Ile-Tyr(SO₃H)-Thr-Gln-OH. It was first isolated from conditioned medium of Asparagus officinalis mesophyll cell cultures, where it functions as a mitogenic factor promoting cell proliferation in low-density plant cell cultures. The biological activity of PSK-α is strictly dependent on the sulfation of its tyrosine residues, as the unsulfated peptide analog shows no mitogenic activity.

PSK-α exhibits high potency with an ED₅₀ of 3.8 × 10^-9 M in asparagus mesophyll cell bioassays. This disulfated peptide represents the first chemically characterized peptidal growth factor in higher plants and demonstrates that peptide-based signaling molecules, similar to those found in animal systems, also play crucial roles in plant cell communication and proliferation regulation.

Note: TFA-removed form of this peptide is not available, as the sulfonate group tends to detach during TFA removal.

• Matsubayashi Y, Sakagami Y. Phytosulfokine, sulfated peptides that induce the proliferation of single mesophyll cells of Asparagus officinalis L. Proc Natl Acad Sci USA. 1996;93(15):7623-7.

Trifluoroacetic acid (TFA) is a common counterion from the purification process using High-Performance Liquid Chromatography (HPLC). The presence of TFA can affect the peptide's net weight, appearance, and solubility.

Impact on Net Weight: The TFA salt contributes to the total mass of the product. In most cases, the peptide content constitutes >80% of the total weight, with TFA accounting for the remainder.

Solubility: TFA salts generally enhance the solubility of peptides in aqueous solutions.

In Biological Assays: For most standard in vitro assays, the residual TFA levels do not cause interference. However, for highly sensitive cellular or biochemical studies, please be aware of its presence.